Adjustable Constant Current Load

A constant current load is used to draw the same amount of current, no matter the voltage. Unlike a resistor, where current increases with voltage. This is great for testing stability and efficiency of power supplies and other devices.

I am currently doing the final testing for this project, and it will be available as a free DIY-pjoject, as soon as I have finished guide and PCB/Layout files for it.




Bill Of Materials

1x         PIC16F877A (Or any Microcontroller with 10-Bit ADC, and 12 I/O-Pins)
1x         4 Mhz Crystal
2x         150n Polyester Film Caps
1x         100u Electrolytic Cap
1x         10u Electrolytic Cap
1x         1x6 Header Connector
1x         10k Multiturn Potentiometer (Anything between 5k and 25k should do)
10x       22 Ohm 1% resistors (The value sets the range, do the math ;])
1x         20k Resistor
1x         1k Resistor
1x         7805 Regulator
1x         1n4001 Rectifying Silicon Diode (Or similar)
1x         TLV271 OpAmp (Any precision >5V "low" offset (<1mV) OpAmp will do)
1x         MTP3055 N-CH MOSFET
1x         HD44780 Controlled 16x2 LCD Display
1x         Heat sink (I used PCB-Mount 41.6 x 50.8 x 25mm with TO220 mounting hole)
1x         85 x 145 mm Double Sided PCB

(1x       25 x 25 mm Single Sided PCB, I use this to convert SMD Devices to leaded, for breadboard testing.)